Li Xiaoyao, Wang Min, Wang Rongyan, Shen Meng, Wu Ping, Fu Zhengqian, Zhu Min, Zhang Lingxia
School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China; State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Ding-xi Road, Shanghai 200050, PR China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China; State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Ding-xi Road, Shanghai 200050, PR China.
J Colloid Interface Sci. 2022 Jun;615:821-830. doi: 10.1016/j.jcis.2022.02.022. Epub 2022 Feb 7.
Increasing the concentration and separation ability of charge carriers in photocatalysts has still been a crucial issue and challenge to achieve high CO photoreduction performance. Here, we construct a distinctive heterojunction between semiconductor (CeO) and metalloid (CuS). It has been discovered that, different from conventional semiconductor and Schottky heterojunctions, in this system, electrons (e) located at the conduction band (CB) of CeO will transfer to the Fermi level in partially occupied band (CB) of CuS and accumulate there. Then, together with transition electrons (e) excited from the CB below Fermi level or fully filled band (B) of CuS, these e will further transfer to the lowest unoccupied band (B) of CuS, finally participate in CO reduction reaction. Because the concentration and separation efficiency of charge carriers has been obviously increased, this heterojunction exhibits remarkably enhanced CO photoreduction performance. In-situ FTIR was conducted to explore the reaction process and the changes of intermediates on the surface of this catalyst during CO photoreduction. Given that this type of heterojunction can only be established between a semiconductor and a metalloid and exhibits special electron transfer behavior, this work really provides an unconventional strategy for the design of photocatalysts with superior CO photoreduction activity.
提高光催化剂中电荷载流子的浓度和分离能力仍然是实现高CO光还原性能的关键问题和挑战。在此，我们在半导体（CeO）和类金属（CuS）之间构建了一种独特的异质结。已发现，与传统半导体和肖特基异质结不同，在该体系中，位于CeO导带（CB）的电子（e）会转移到CuS部分占据能带（CB）的费米能级并在那里积累。然后，这些电子与从CuS费米能级以下的导带或完全填满的能带（B）激发的跃迁电子（e）一起，进一步转移到CuS的最低未占据能带（B），最终参与CO还原反应。由于电荷载流子的浓度和分离效率明显提高，这种异质结表现出显著增强的CO光还原性能。进行了原位傅里叶变换红外光谱（FTIR）以探索CO光还原过程以及该催化剂表面中间体的变化。鉴于这种类型的异质结只能在半导体和类金属之间建立且表现出特殊的电子转移行为，这项工作确实为设计具有优异CO光还原活性的光催化剂提供了一种非常规策略。
